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RSI Indicator Chart

Chart the Relative Strength Index to gauge overbought and oversold momentum.

What is the RSI indicator?

The Relative Strength Index (RSI) is a momentum oscillator that measures the speed and size of recent price changes on a 0–100 scale. It compares average gains to average losses over a look-back window (typically 14 periods). Readings above 70 are conventionally 'overbought' and below 30 'oversold', while divergence between RSI and price is often read as an early warning of a trend change.

14-period RSItime-series

Illustrative 14-period RSI oscillating between overbought (70) and oversold (30). Synthetic data for demonstration.

RSI, introduced by J. Welles Wilder in 1978, remains one of the most widely used momentum indicators. It reframes raw price into a bounded oscillator so you can compare momentum across very different instruments on the same scale. This tool charts a 14-period RSI with the classic 70/30 bands.

How RSI is calculated

RSI is derived from the ratio of average gains to average losses over the look-back window: RSI = 100 − 100 / (1 + RS), where RS is average gain divided by average loss. Wilder's smoothing (a modified moving average) is applied so each new bar updates the averages incrementally rather than recomputing the whole window.

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The default 14-period setting balances responsiveness and stability. Shortening it (e.g. to 7) makes RSI swing more violently and hit the extremes more often; lengthening it (e.g. to 21) smooths the line and produces fewer signals. The bounded 0–100 range is what makes RSI comparable across assets.

Overbought, oversold, and the trap

The 70/30 thresholds are the textbook overbought/oversold levels, but they are not automatic buy/sell triggers. In a strong uptrend RSI can sit above 70 for weeks; selling every time it crosses 70 would be costly. Practitioners often shift the bands (e.g. 80/40 in an uptrend) or use RSI only alongside trend context.

Divergence — the higher-value signal

Many analysts value RSI most for divergence: when price makes a new high but RSI makes a lower high, upward momentum is fading even though price is still rising. Bullish divergence is the mirror image at lows. Quadesto lets you compute RSI on any uploaded series and plot it beneath the price so divergences are easy to spot.

Build this with your own data

Upload a CSV or connect a live source, and Quadesto renders this exact chart — styled, computed, and embeddable in your reports and newsletters. Free to start.

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Frequently asked questions

What RSI level is overbought?
Conventionally, an RSI above 70 is considered overbought and below 30 oversold. These are guidelines, not signals — in strong trends RSI can remain extended far longer than expected, so it is best used with trend context.
What is the best RSI period?
The default is 14. Shorter periods (7–9) make RSI more sensitive and produce more signals; longer periods (21+) smooth it out. The right choice depends on your timeframe and how much noise you can tolerate.
What is RSI divergence?
Divergence is when price and RSI move in opposite directions — for example, price sets a higher high while RSI sets a lower high. It suggests weakening momentum and is often used as an early reversal warning.
Can RSI be used on any asset?
Yes. Because RSI is bounded 0–100 and derived from returns, it applies to equities, FX, crypto, commodities, and rates alike, and lets you compare momentum across them on one scale.
How do I add RSI to my own data?
Upload your price series to Quadesto and add an RSI derived column with your chosen period. Plot it as its own panel with 70/30 reference bands and embed it wherever you publish.